This invention relates to a tool handle used in conjunction with a variety of elongated shanks and appropriate tips thereon for driving screws, or other fasteners and the like. Optimally, such handles convert the twisting force and forward pressure of the operator's hand into a rotational and axial motion of the shank with sufficient torque and axial thrust to drive the fastener. The handle should also be sufficiently maneuverable to facilitate accurate mating of the fastener and the tip, and to afford sufficient smoothness of twisting to permit numerous quick rotations at low torque when required.
Often, to achieve the high torque required for the final tightening or initial loosening of a fastener, designers have provided the tool handle with deep grooves or knurling to prevent slippage of the user's hand over the handle. Others have added wings that flip out, sheaths which fold up, handles which convert into "T-shaped" configurations, and handles which convert into "L-shaped" configurations in order to provide additional leverage to achieve the desired torque. These methods have their drawbacks. The deep grooves can only supply limited additional torque before becoming physically uncomfortable to the user. Winged, "T" or "L" designs often require the use of a second hand to convert to the high-leverage configuration. This impairs the utility of the tool in close quarters, such as when the fastener is being driven parallel to a closely adjacent surface. Some latch-release "L" designs can be converted by a single hand, but the latch release operation prevents smooth shifting between high and low leverage configurations. Winged or "T" designs require additional clearance space for the extended portions on opposite sides of the handle.
Often, such handle constructions cannot be used in the palm of a single hand because the awkward position of the hand during use makes it hard to align the shank tip with the mating part of the fastener. It is often desirable to use a driver in both conventional and high-leverage positions while driving a single fastener. The time wasted in converting the wrench during the middle of the driving operation is very costly, often resulting in the user utilizing the tool in just one position all the time and/or using two hands rather than one.